Lect-7-FM_07 - Types of AM : 1.Ordinary AM Carrier and both...

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Types of AM : 1.Ordinary AM – Carrier and both sidebands. 2. DSB-SC – Double Sideband Suppressed Carrier. 3. SSB-SC – Single sideband suppressed Carrier. 4. VSB – Vestigial Sideband. VSB is a compromise between DSB & SSB.
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VSB Signal : VSB modulation is used for terrestrial TV broadcast systems. The video signal requires a bandwidth of 4.5MHz with a sizeable power in the low frequency region. Since it is difficult to suppress one sideband completely to realize a filter a ‘vestige’ or part of the other sideband is transmitted along with one sideband.
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VSB Signal for TV Transmission
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Signal Shaping in the receiver.
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Features of AM: It is a linear modulation system The transmitted spectrum is just the translated version of the Base band spectrum The Bandwidth never exceeds twice the message bandwidth Increase in output SNR only by increasing transmitted signal power
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Lecture – 7 Frequency Modulation FM Spectrum & its features
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Frequency Modulation: )] ( cos[ )] ( cos[ ) ( t t c c A t c A t x φ ϖ θ + = = ) ( ) ( t t c t + = dt d c i dt d + = = dt d c f i f π 2 1 + = If Φ(t) is proportional to the message signal, we call it Phase modulation If (dΦ/dt) is proportional to the message signal m(t), we call it Frequency modulation b a
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)] ( cos[ ) ( t m p k t c c
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This note was uploaded on 09/24/2010 for the course MATHEMATIC AAOC C222 taught by Professor Prof.dilipkumarsatpathi during the Fall '07 term at Birla Institute of Technology & Science, Pilani - Hyderabad.

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Lect-7-FM_07 - Types of AM : 1.Ordinary AM Carrier and both...

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